This invention relates generally to poppet valve assemblies for controlling flow therethrough of a fluid, such as gasoline from a gasoline tank truck into an underground storage tank at a filing station.
In order to fill one or more underground storage tanks at a gasoline service station, a cargo tank truck typically pulls into the service station and unloads the fuel from the truck into the underground storage tank or tanks. Such a cargo tank truck commonly has multiple fuel storage compartments, each compartment having a cover and a pipe located below the tank to which is connected a valve assembly. The valve assembly is commonly a poppet valve assembly which is opened and closed by the truck""s driver via a handle extending upwardly from the valve assembly. In order to unload fuel from one of the truck""s fuel storage compartments into the underground storage tank, the truck driver or operator connects two hoses from the truck to elbows on the underground storage tank. One of the hoses is a vapor recovery hose which returns vapors to the truck from the underground storage tank. The other hose is connected at one end to one of the valve assemblies on the truck via an adaptor and at the other end to the underground storage tank. In order to cause fuel to flow through this hose to the underground storage tank, the truck driver simply opens the valve assembly.
Commonly, each underground storage tank has a valve therein, which closes when the underground storage tank is sufficiently full, thereby stopping the flow of fuel from the truck to the underground storage tank. After this valve in the underground storage tank closes, gasoline or fuel is still present in the line or hose extending between the cargo tank truck compartment and the underground storage tank. In order to prevent gasoline from overflowing onto the pavement of the service station, the operator of the cargo tank truck closes the valve assembly on the cargo truck and opens one of the cam arms on the adaptor, thereby allowing air to enter the hose. The air in the hose forces the fuel in the hose towards the underground storage tank and through a bleeder hole in the valve in the underground storage tank. After a sufficient time period has passed, the operator simply disconnects the adaptor from the valve assembly, removes the hose from the elbow of the underground storage tank and places the hose on the truck. After the vapor recovery hose is disconnected and placed on the truck the driver may move to the next location.
In order to prevent an accidental overflow, it is desirable for the cargo tank truck operator or driver to know if liquid is present in the valve assembly, and if liquid is flowing through the valve assembly. The operator does not want to disconnect the adaptor from the valve assembly of the truck with liquid present in the valve assembly or flowing therethrough. Consequently, it is advantageous for the driver to know whether fluid is present in the valve assembly and whether the flow of fuel through the hose has stopped.
Valve assemblies are known which have a sight glass built therein in which a float is located in order to indicate liquid presence in the valve assembly. The float commonly comprises a hollow ball. When liquid is present in the sight glass, the float raises because its density is less than the density of gasoline. Thus, the operator is able to tell whether fuel is present in the valve assembly.
In addition, one valve assembly manufacturer has incorporated a flow indicator into its valve assembly. This flow indicator contains three flourescent orange balls in a sight glass which rise when fluid is present in the sight glass and hence in the valve. In addition, the orange balls rotate when fluid is flowing through the valve and through the sight glass. In order to determine if fluid is flowing through this valve assembly, one must determine whether the balls are rotating. Often this is difficult to do given the small size of the balls so that, in order to make a determination, one must be very close to the valve assembly. The truck""s driver is not able to determine whether the orange balls are rotating from a distance.
Therefore, it has been one objective of the present invention to provide a poppet valve assembly having a flow indicator which may be read from a distance quickly and easily.
It is a further objective of the present invention to provide a poppet valve assembly having a fluid indicator and a flow indicator which may be read from a distance quickly and easily.
The invention of this application which accomplishes these and other objectives comprises a poppet valve assembly for use on a fuel tanker truck for unloading fuel from the truck into an underground storage tank at a service station.
The poppet valve assembly of the present invention comprises a housing having a flow passage therethrough. The flow passage has a central axis.
The poppet valve assembly further comprises a poppet structure for controlling fluid flow through the flow passage The poppet structure is operatively coupled to a handle so that when an operator pulls on the handle, the poppet structure moves axially, thereby opening the valve and enabling fuel to flow through the flow passage.
A sight glass assembly is mounted to the housing on the exterior of the housing. The sight glass assembly comprises a sight glass having an interior in which is located a flow indicator and a fluid indicator. The sight glass is preferably made of plastic but may be made of any see through material such as glass. The flow indicator is a dumpbell shaped object preferably made of nylon which moves in the interior of the sight glass. However, the flow indicator may be made of any other suitable material. A fluid indicator in the form of a hollow ball made of polyethylene moves in the interior of the sight glass above the flow indicator. However, the fluid indicator may be made of any other suitable material.
The shape/configuration of the interior of the sight glass is such that the fluid indicator is always located above the flow indicator. The fluid indicator has a density less than the density of fuel, so that it floats when fuel fills the interior of the sight glass. The flow indicator is denser than the density of fuel, so that it will only raise when a threshold flow rate occurs through the interior of the sight glass. The fluid indicator is preferably a green spherical-shaped ball, but may be made of other colors or other shapes. Similarly, the flow indicator is preferably a dumbbell-shaped red object. The contrast between the red and green colors enables a truck operator to determine the presence of fluid in the sight glass and whether fuel is flowing through the sight glass easily and at a distance.
When the flow rate through the flow passage of the housing reaches a threshold value, typically 30 gallons per minute, fluid flows through a flow channel which includes the interior of the sight glass. The flow channel is in fluid communication with the flow passage of the valve assembly. The flow channel has an inlet extending between the flow passage and a lower portion of the interior of the sight glass. The flow channel also has an outlet extending between the flow passage and an upper portion of the interior of the sight glass, so that fluid flows upwardly through the interior of the sight glass when the threshold flow rate in the flow passage is reached. A portion of the outlet extends generally parallel to the central axis of the flow passage and the inlet of the flow channel extends generally perpendicular to the central axis of the flow passage, thereby creating a pressure differential so that fluid flows through the flow channel due to a Venturi effect.